Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Sale-Leaseback (Details)

v3.8.0.1
Summary of Significant Accounting Policies - Sale-Leaseback (Details)
 3 Months Ended 9 Months Ended
Sep. 30, 2017
USD ($)
project
Sep. 30, 2016
USD ($)
project
Sep. 30, 2017
USD ($)
Sep. 30, 2016
USD ($)
Dec. 31, 2016
USD ($)
Sale Leaseback Transaction [Line Items]          
Number of Solar PV Projects Sold | project 3 1      
Sale Price $ 9,157,000 $ 6,037,000 $ 30,611,000 $ 17,045,000  
Deferred Gain Recorded 642,000 333,000 642,000 333,000  
Deferred Loss Recorded 0 0      
Capital Lease Asset/Liability Recorded $ 4,114,000 $ 3,158,000 4,114,000 3,158,000  
Initial Lease Term 20 years 25 years      
Property and equipment, net $ 4,830,000   $ 4,830,000   $ 5,018,000
Solar Photovoltaic Projects          
Sale Leaseback Transaction [Line Items]          
Maximum combined funding amount   $ 100,000,000   $ 100,000,000  
Initial Lease Term       20 years  
Percentage of fair value threshold, integral equipment     10.00%    
Net amortization expense (25,000) (6,000) $ (49,000) $ (37,000)  
Deferred loss, short-term, net 109,000   109,000   53,000
Deferred loss, long-term, net 1,943,000   1,943,000   956,000
Capital lease liabilities, short-term 3,451,000   3,451,000   2,185,000
Capital lease liabilities, long-term 24,857,000   24,857,000   12,462,000
Deferred gain, short-term, net 195,000   195,000   89,000
Deferred gain, long-term, net 3,195,000   3,195,000   1,632,000
Solar Photovoltaic Projects | Assets Held under Capital Leases          
Sale Leaseback Transaction [Line Items]          
Property and equipment, net 28,800,000   $ 28,800,000   $ 14,896,000
Solar Photovoltaic Projects | Minimum          
Sale Leaseback Transaction [Line Items]          
Initial Lease Term     10 years    
Lease Payment 13,000 2,000      
Solar Photovoltaic Projects | Maximum          
Sale Leaseback Transaction [Line Items]          
Initial Lease Term     20 years    
Lease Payment $ 231,000 $ 397,000